spare tire on 35+ year old car

My understanding is that tire rubber is not safe to drive on after about 10 years from date of manufacture (the tire, not the car). I still have my original spare, but I wouldn't trust it at all.

Options… full size spare?

I would trust it for keeping under the 35mph speed limit i think it has. Rubber deteriorates quickly when exposed to UV so if it's been kept out of the sun and kept dry, i'd still use one in an emergency.

I've only had to use the one in my 84T once, but will inflate it every few years to make sure it's not cracked and holds air.

If you check out the YT channel, ColdWarMotors, that guy treats old tires like heirlooms and runs tires from the 60's and 70's on his cars, of course most of them don't leave the yard tho…

Did all years of Z31 come with the space savor spare? I've never messed with my spare but the previous owners left me two tire inflator bottles. Is that just a bottle of air? Can you inflate the spare tire with air?

Yes they all came with just the compact hid-a-spare, I have never used mine. I have had just one flat in 36 years but lost more than one tire and had to get towed. I had the bottle of air that I lost at some point when the spare well was being rebuilt due to rust. I think I am going to get the tire size off the tire and buy a new one off Tirerack, they sell replacements and add a small air pump. I just check with them and they have them in all sizes, for sure I do not run tires past 7 years actually.I had some nice Bridgestone SO3 ZR rated tires on my car and they were about 8 years old with plenty of tread left, I had to hit the brakes hard and figured out quckly that they were not so good anymore!

They did have a few variations in Europe. I think some Z31s sold in France had a larger spare wheel, either just in the trunk or maybe even somehow mounted under the car. Not sure about that. And it may have been in the UK where some cars instead came with run-on-flat tires and no spare at all. Some cars had a cover for the spare wheel so these might have just been in the trunk strapped down.

Recently in one of the Facebook groups someone found a 2010 Elantra space saver spare that seemed to be an ok fit. Just has a center bore of 67.1 instead of 66.1 so it would need a hub centering ring for that.

Well in US for sure none ever had anything but hid-a-spare, doubtful any Z31 had runflats, those were not really out until the 90's, first invented in late 80's and only highest end German cars had those. I wasn't able to find an exact fit of the 155/90 15 but there are 80 series available. I am not sure that I would really be able to get far anyways now I have 16" wheels, but I do plan to talk to TireRack about something better than the 36 year old tire i have in the spare well. I do occasionally drive the old girl from SF to LA and that would be a long tow!

All I know is that runflats are mentioned in the owner's manual. But it was a rare case anyway, I think even in Europe most Z31s still had the same kind of spare wheel.

I just inflated and took a short drive (2 miles at about 30-35mph) on the unused original spare in my 1986 a few weeks ago. After sitting collapsed for 35 years, it inflated extremely lopsided and had brown oxidized mold release wax flaking off the whole surface. I let it sit inflated overnight, which gave the shape enough time to even out, re-checked the pressure,and brushed off all of the loose wax before my short test. With the oxidized wax brushed away, the rubber itself looked pristine.

I have no plan to drive on it again, but would feel comfortable using it for low speed driving if there were an emergency. Going forward I will probably pull it out every few years and inflate it in order to exercise the rubber a bit and make sure it still holds pressure. While the compressed gas canister that came with the car is still full, I took that out of the vehicle about 10 years ago and put an air pump in its place, as that is much more generally useful to have on hand anyways. I've also got a plug kit and some sealer in the car, so I consider the original spare a last resort.

Read the can on that sealer… some of those are corrosive to the rims. They'll have some verbiage that the tire needs to be removed and the wheel cleaned after use.

For sure I am going to get one ordered next time I have to go to my mechanic for an oil change, he's a Tirerack installer, I also plan to find a good 12v powered inflator vs can of air. Interesting Kaur that the manual mentioned something about TD Runflat and it looks like it is positioned under the back, never saw that before. I never remembered seeing a RF tire until the 90's.